barrel works wonders. i installed it with the stock hop up, and it gave me great results. only thing is, this does not work with the PDi hop up chamber. so buy this if you want to continue to use the stock hop up unit.
Before installing this barrel my sniper never really shot right. After installing it, I can hit a Mountain Dew can at 150ft 9 out of 10 times. It also helps when you have an fps of 540 with .25s